Chris Welty wrote:
>
> Axel Polleres wrote:
>>>> I was hoping we could get BLD a usable rules language for RDF,
>>>> compatible with SPARQL. (And similar problems will arise if we
>>>> pursue to
>>>> suggest RIF to the RDB2RDF people: If we as a working group approach
>>>> them and say: look at RIF, we should then not be in the position that,
>>>> if they agree to do so, having to answer them: "BUT, BTW RIF doesn't
>>>> work for that, you need to do your own dialect from scratch, your
>>>> problem...")
>>>>
>>>> I see some very fundamental issues here.
>>>
>>> I would be very interested to see whether there are any features
>>> required by RDB2RDF that are not provided by RIF.
>>
>> I have no concrete example as of now, but my rationale is: if we run
>> into troubles with SPARQL, we might also run into troubles with SQL,
>> since they share many underlying assumptions.
>
> If you're going to judge BLD by itself in terms of its suitability to
> address the requirements of datatabase query language you will certainly
> find it falls short. So don't set unreasonable expectations - BLD is
> the *basic* *logic* dialect. I realize you know this, but when you say
> "I was hoping we could get BLD a usable rules language for RDF,
> compatible with SPARQL," it makes me think you've forgotten.
>
> The RIF approach to something like RDB2RDF would be to start with BLD
> and then extend it to a dialect that supports the additional things they
> need. And depending on how hard you stress "need" (as opposed to "want"
> or "would find convenient") you will probably find the dialect is not a
> big extension.
I agree.
BTW: An example of what they explicitly mentioned and which is not
covered per se in RIF are aggregates.
> [As an aside, I was just working with some DB folks last week here (on
> something unrelated) and overheard the comment, "most experts know the
> 2/3 of SQL to avoid". SPARQL also has its things to avoid.]
>
> -Chris
>
--
Dr. Axel Polleres
Digital Enterprise Research Institute, National University of Ireland,
Galway
email: axel.polleres@deri.org url: http://www.polleres.net/